Rechargeable cells, such as the nickel-cadmium cells, have a relatively constant potential during discharge and can be recharged many times, thus extending their useful life. In general, any secondary or rechargeable cell contains a combination of active materials which can be electrolytically oxidized and reduced repeatedly. In rechargeable cells, reactions at both electrodes are reversible and the input of current in the appropriate direction from an outside source will reverse the discharge reaction and, in effect, recharge the electrodes.
The rechargeable cells have been used in various type devices, such as toys, calculators, radios and other types of power-operated devices. Many of the power-operated devices on the market today have been designed to accommodate cylindrical cells of the "AA", "C", and "D" size. These sizes have now become standard-type cell sizes having overall dimensions which can be found in various publications, such as The American National Standard Specifications For Dry Cell Batteries--ANSI C18.1-1969 published by the American National Standards Institute, Inc., New York, N. Y.
There are many different types of chargers on the market which employ standard transformer and half-wave or full-wave rectifier circuit means for providing a direct current for charging rechargeable type cells or batteries. The cell holders of the chargers are generally designed to accommodate a single size cell. Recently, cell holders have been designed which can accommodate two or more standard size cells through the use of adapters. For example, one cell holder is designed to accommodate "D" size cells and, in addition, comes equipped with a hollow "D" size shell into which a "C" size cell can be placed. The hollow shell is constructed such that the terminals of the "C" size cell are electronically contacted to terminals on the shell thereby providing the inner cell with an outer "D" size shell configuration. Thus the "C" size cell can be charged in the "D" size cell adapter.
One of the objects of this invention is to provide a multi-cell charger that does not require any adapter for charging "AA", "C" and "D" size rechargeable cells.
Another object of this invention is to provide a rechargeable cell holder that is constructed such that it can accommodate either "D" size, "C" size or "AA" size cell, but not combinations of these size cells at the same time.
Another object of this invention is to provide a rechargeable cell holder having a groove for accommodating a "D" size cell and when a "C" size or "AA" size cell is extended across the groove, the groove can be used to provide a pair of recesses disposed on both sides of the cell which can be utilized to facilitate gripping and removal of the cell from the holder.
Another object of this invention is to provide a rechargeable cell holder having a groove for accommodating a "C" size cell and a groove for accommodating an "AA" size cell and when a "D" size cell is extended across both of the grooves, each of the grooves can be used to provide a pair of recesses disposed on both sides of the "D" cell which can be utilized to facilitate gripping and removal of the cell from the holder.